The present invention relates to systems and methods for evaluating optical systems, parts or systems for tampering, defective design, fraudulent representations of capability, specification misrepresentation, or counterfeit parts.
Some embodiments can be used for evaluating defective or misrepresentations of specification compliance. For example, the Government could use the invention to determine if a supplier of military and/or government agency optics knowingly sold defective optics such as optics including red-dot sights. Defects can include a condition referred to as thermal drift where the sight's point of aim differs from its point of impact when exposed to temperature changes. For example, a gun that was sighted in the morning at 50 degrees F. would not hold accurate when the temperature ranged up to 100 degrees F. by the afternoon. After learning of this problem, it was necessary to quantifiably test optics to determine if they have the thermal drift condition.
One existing method of testing for thermal drift includes placing a sight in a freezer or heating chamber, pulling the sight out, putting it on a firearm, and firing at a target. One problem with this existing method includes not accounting for the temperature of the firearm or sight mounting rail where the sight is attached. Repeatability of results is impeded due to the need to take the sight on and off the firearm or its mounting rail (requires re-zeroing of the sight, etc.). If a testing environment has experienced a thermal change, a platform the sight or device is attached to will also have experienced some changes due to expansion or contraction of the materials.
Embodiments of the invention address significant problems with various existing methods for testing thermal stability of a sight or other visual augmentation devices (e.g., magnified optics or lasers). Testing based on heating then cooling then firing of a firearm introduces additional variables that are not repeatable in a laboratory setting. For example, various factors impacting such testing include sight picture, trigger squeeze, breath holding, density altitude, bullet quality, allowable dispersion from lot-to-lot in ammunition, etc. This type of test method is very heavily reliant on the skill of the user and other environmental factors.
In one exemplary embodiment of the present disclosure, an exemplary mounting rail is disposed inside of an exemplary thermal chamber along with a unit under test (UUT), e.g., visual augmentation device or sight. Such a mounting rail can be formed from a dense material that is resistant to thermal changes, but if its position changes due to thermal expansion, this expansion or movement will be minimal (e.g., within an error budget).
Exemplary embodiments of this disclosure substantially reduce or eliminate human factors in process controls associated with various types of in-situ testing. Reductions of errors can approach or exceed an order of magnitude or better in measurement resolution, repeatability, and reliability results. Various embodiments provide a capability for evaluating parts or systems to characterize performance of a device or system under test which can be useful for a variety of evaluations. Exemplary evaluations can include evaluating for specification adherence, tampering, misrepresentation, defects, fraudulent claims or counterfeit parts. In particular, various exemplary systems and methods are provided including test stations and methods for quantifying thermal drift or establishing thermal stability of visual augmentation systems, such as red dot sights, lasers, etc.
Additional features and advantages of the present invention will become apparent to those skilled in the art upon consideration of the following detailed description of the illustrative embodiment exemplifying the best mode of carrying out the invention as presently perceived.